Endothelial progenitor cells (EPC) stent implantation in high-risk patients with no option for drug-eluting stents seems encouraging, a new study has concluded. The results were published in EuroIntervention. The Genous bioengineered stent, the authors wrote, presented “satisfactory clinical outcomes both at short and at long-term follow-up”.

The study enrolled high-risk patients with underlying clinical conditions who cannot be treated with drug-eluting stents and the accompanying requirement of long-term dual antiplatelet therapy.

The major adverse cardiac events free survival rate in patients treated with the Genous stent was 80.6% after one year. Between year one and year two, no additional major adverse cardiac events were observed. In patients who underwent surgical treatment shortly after percutaneous coronary intervention, no peri-operative major adverse cardiac events or thrombotic events occurred.

Despite a very short period of dual antiplatelet therapy use of 15 to 30 days, there were no cases of sub-acute, late or very late stent thrombosis in treated patients. The cumulative incidence of cardiac death was 1.6%, which is low considering the high-risk patient population.

“The Genous stent is an important and extremely attractive option for interventional cardiologists to safely manage high-risk patients who are contraindicated for prolonged dual antiplatelet therapy and, therefore, should not receive a drug-eluting stent,” said Paolo Scacciatella, Molinette Hospital Turin, Italy, and principal investigator of the study. “This is the first study that demonstrates the feasibility and efficacy of the device in this particular segment of patients who are challenging to treat.”

Emanuele Meliga, Ordine Mauriziano Hospital, Turin, Italy, added, “We have observed that the Genous stent, which accelerates the natural healing process, enables a shorter post-procedural period of dual antiplatelet therapy without increasing the risk of late or very late stent thrombosis and without causing dangerous delays for patients who require noncardiac surgery shortly after percutaneous coronary intervention.”

Data from other two studies demonstrated that the Genous stent increases endothelial coverage and reduces thrombogenicity as compared to bare metal stents by enhancing the specific binding of CD34+ EPC.

Eric J Duckers, Thoraxcenter, Erasmus University Medical Centre in Rotterdam, The Netherlands, and co-investigators Saami Yazdani, and Renu Virmani, CVPath Institute, Gaithersburg, USA, presented collaborative data at the American Heart Association’s Scientific Sessions 2010 that demonstrated the mechanism of early EPC capture and reduced thrombogenicity of the Genous stent in human circulating blood in an ex vivo arteriovenous shunt model.

The data showed that the device bound significantly more cells and had markedly less thrombus than bare metal stents. Gene expression analysis showed that endothelial specific markers were significantly increased and thrombogenic markers were significantly decreased with the Genous stent compared to bare metal stents.

“These data demonstrate the importance of CD34+ cells for endothelialisation and the prevention of thrombosis,” said Duckers. “This mechanism of early endothelisation supports the design of the unique EPC capture technology of Genous.”

“We were able to see a significant difference between the Genous stent and the bare metal stent in promoting EPC capture and reducing acute thrombogenicity,” said Virmani. “The Genous stent appears to not only promote the adhesion of human EPCs, but also reduces the adhesion of fibrin, platelets and inflammatory cells, which is important for the prevention of thrombus.”

In a second study, increased cell coverage was observed for the Genous stent compared to bare metal stents in vivo. The study, carried out in rabbits, further showed the increased expression of endothelial specific genes for the Genous stent compared to bare metal stents. The study was designed to investigate the gene expression patterns of endothelial specific genes and endothelial coverage by scanning electron microscopy and qPCR after stents were implanted in carotid arteries for seven days.